1. Field of the Invention
The present invention relates to a gas pressure-to-hydraulic (hereinafter referred to as oil) pressure converter system in an oil pressure actuator, which converts a gas pressure into an oil pressure to drive the actuator and thus a functional subject such as a valve.
2. Description of the Prior Art
It is well known in a wide range of industrial fields that this type of a gas pressure-to-oil pressure converter is utilized to drive an actuator. By way of an oil pipe line system, the above-described type of the actuator drive system is conventionally employed to actuate a ball valve or a gate valve disposed in a particular position in the pipe line.
As viewed from an exemplary pipe line system of FIG. 1, an actuator 3 is provided for a ball valve or a gate valve 2 which is intended for actuation and disposed in a particular point in a pipe line. The inner gas pressure of the pipe line 1 is stored within a power storage reservoir 4 for a while and then the gas pressure of the reservoir 4 is exerted on one part of gas-oil reservoirs 6, 7 for conversion into an oil pressure upon actuation of the control valve 5. Application of such an oil pressure onto the actuator 3 via a hand pump 8, therefore, permits the actuator 3 to operate the ball valve or gate valve 2.
With the above described actuator drive mechanism, oil tends to somewhat leak out from an oil cylinder section of the actuator 3, the hand pump 8 and so on and oil, for example, moves from the one gas-oil reservoir 6 to the other 7, deteriorating the normal performance of the drive mechanism. This results in a substantial change in the speed of valve opening and closing and eventually causes serious problems in the pipe line service used with the pipe line.